feat: configurable trip reminders, admin full access, and enhanced audit logging

- Add configurable trip reminder days (1, 3, 9 or custom up to 30) settable by trip owner
- Grant administrators full access to edit, archive, delete, view and list all trips
- Show trip owner email in audit logs and docker logs when admin edits/deletes another user's trip
- Show target user email in audit logs when admin edits or deletes a user account
- Use email instead of username in all notifications (Discord/Slack/email) to avoid ambiguity
- Grey out notification event toggles when no SMTP/webhook is configured
- Grey out trip reminder selector when notifications are disabled
- Skip local admin account creation when OIDC_ONLY=true with OIDC configured
- Conditional scheduler logging: show disabled reason or active reminder count
- Log per-owner reminder creation/update in docker logs
- Demote 401/403 HTTP errors to DEBUG log level to reduce noise
- Hide edit/archive/delete buttons for non-owner invited users on trip cards
- Fix literal "0" rendering on trip cards from SQLite numeric is_owner field
- Add missing translation keys across all 14 language files

Made-with: Cursor

server/src/db/schema.ts

@@ -41,6 +41,7 @@ function createTables(db: Database.Database): void {
       currency TEXT DEFAULT 'EUR',
       cover_image TEXT,
       is_archived INTEGER DEFAULT 0,
+      reminder_days INTEGER DEFAULT 3,
       created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
       updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
     );